Very plausible, Bob, but not necessarily the definitive analysis/conclusion. So many variables. The truth is that we shall likely never know.

You are a bonifide engineer...me, just a mere mechancial engineering technician...so I'd like your take on the affect of the upgunning from the 13-inch wheels Mickey designed the car around to the 15-inch rims as stipulated by USAC. Much has been made of this being a huge technical change but was it a crippling element? The ruling concerned the wheel specification. What were the relative dimensions of the actual tires involved? That, to my mind, is the critical factor. If the section heights of the tires were more or less equal, the larger radius wheels would have elevated the car just one inch higher in terms of ride height, not two. Could this not be compensated for in a revised suspension setup with reasonable expectation of retaining performance? Would that extra inch's worth of ground clearance be enough to turn the car from a decent-handling car into a nightmare?

Manfred,

I started to reply to your questions but it has already evolved into a massive treatise on vehicle dynamics filled with sweeping assumptions. To really get to the bottom of the issue we need more specific information. (But the little newspaper clipping that HistoricMustang has posted above gives you a clue as to what the Thompson cars were up against.)

I'm going to be away in Boston watching our daughter row in the "Head of the Charles" regatta (for Drexel University) so I won't have much of a chance to address this further until next week. But in the meantime I have a request for help from the followers of this thread that might help.

When I first became a racing fanatic back in the late sixties I took a book out of the library that went into great detail about the events of USAC racing in general and the Indy 500 in particular. I remember that it went into great detail about the controversies, both technical and personal, surrounding the 1964 Indy 500. There was a great deal of discussion about the struggles of the Thompson team and also of the tire and chassis issues affecting many of the top teams. One thing that has stuck with me was that it related some stories that didn't reflect well on A.J. Foyt.

It didn't just deal with the 1964 race but also talked a great deal about the dangers of open wheel racing during that era and all of the drivers who perished. I specifically remember a very personal story attributed to Chuck Rodee's wife that foreshadowed his death in practice (or qualifying?) at the 1966 500.

I had always thought that the book that contained all of this was "Ford: The Dust and the Glory" by Leo Levine. However, I now have a copy of that book and it isn't the book I am thinking of.

This is really a stretch I know. To identify a book from forty years ago based on such sketchy recollections is asking a lot. But if I am right it contained a considerable amount of valuable information relevant to this topic.

Why are you wasting your time? Where is your evidence that the Thompson was a "nightmare to drive", or "aerodynamically instable"?

I have also read this and now found the reference in Jack Brabham's book. It quotes Masten Gregory trying to qualify the car and then talking to Jack. "What's it like?" Masten pulled a face and said, "It's absolutely an accident going somewhere to happen. Under full tanks it's totally terrifying..." Jack continues "All the way round the rolling lap before the start - mindful of Masten's warning - I just kept my eyes riveted on that red car, knowing it was brimful of fuel. It was visibly very unsteady. I did not take my eyes off it. We came out of Turn Four, green flags and we were racing. My eyes were still glued on that odd-looking car a couple of rows ahead. Dave McDonald nearly lost it in Turn Two, but caught it. In Turn Three he was again all over the place. Then, coming out of Turn Four, it happened. Dave's ultra-low Thompson car flicked broadside and he lost it."

This description indicates that the car's problems were exacerbated by the full fuel load and also that the handling was poor even at slower speeds.

I have also read this and now found the reference in Jack Brabham's book. It quotes Masten Gregory trying to qualify the car and then talking to Jack. "What's it like?" Masten pulled a face and said, "It's absolutely an accident going somewhere to happen. Under full tanks it's totally terrifying..." Jack continues "All the way round the rolling lap before the start - mindful of Masten's warning - I just kept my eyes riveted on that red car, knowing it was brimful of fuel. It was visibly very unsteady. I did not take my eyes off it. We came out of Turn Four, green flags and we were racing. My eyes were still glued on that odd-looking car a couple of rows ahead. Dave McDonald nearly lost it in Turn Two, but caught it. In Turn Three he was again all over the place. Then, coming out of Turn Four, it happened. Dave's ultra-low Thompson car flicked broadside and he lost it."

This description indicates that the car's problems were exacerbated by the full fuel load and also that the handling was poor even at slower speeds.

XJ13

Earlier in this post we had photos with the location of key cars listed and from them it appeared Jack Brabham could not have seen Dave spin coming off of turn 4 since Jack himself was barely into turn 3.

The one thing you have confirmed is when Masten told Jack about the cars and their handling problems. Perhaps Ovi can repost those pics

Earlier in this post we had photos with the location of key cars listed and from them it appeared Jack Brabham could not have seen Dave spin coming off of turn 4 since Jack himself was barely into turn 3.

The one thing you have confirmed is when Masten told Jack about the cars and their handling problems. Perhaps Ovi can repost those pics

If that were even remotely correct he would have seen the explosion and had time to come to a complete standstill prior to the crash scene. Maybe he just plowed on through there for the fun of it? Barely into turn three and still drives through a fireball how far into the distance? No doubt Jack just made it all up years later. Can someone tell this post just how far it is from "into turn three" to the exit of turn 4 please? Perhaps someone can post the entire page from the book so everyone can read the full text including how he braked and swerved.

I think that you just rephrased the one thought that went through about everyone's mind who read it. But all evidence buried in this thread seems to confirm the obserbvation.about 50 gallons of fuel can cause a fire that big under the right circumstances

Read the following link: it's an article published in the Summer of 1964 already. It was known by then already.

WOW! There it is! Certainly doesn't seem to be well securred in the chassis. 290 pounds of fuel.It looks just like a bag thrown into a box. Doesn't take too much imagination to see it bursting on impact.Terrific photo!ZOOOM

WOW! There it is! Certainly doesn't seem to be well securred in the chassis. 290 pounds of fuel.It looks just like a bag thrown into a box. Doesn't take too much imagination to see it bursting on impact.Terrific photo!ZOOOM

Ironically, the more firmly the bag was fixed to the chassis the more likely it would be to burst on impact. To illustrate the logic, imagine it wasn't secured at all and was free to move - it would have "rode with the punch" and not burst.

Good, I am glad some people have learnt a little bit about fires using gas or petrol. This whole "under the right conditions" nonsense needs to stop now. Some of the posts here are of a conspiracy theory mentality and do them no credit at all. Please stop now. The car was handling badly even at slower speeds. The poor guy lost it as many drivers would have and carrying a heavy fuel load it blew up on impact.
How can any of you not see this simple truth?

There is nothing wrong with this fuel vessel by 1964 standards. It's a standard helicopter fuel bladder of the period and it is mounted in the prescribed manner. The photo shows the bladder only partially installed. Fully assembled, the bladder is completely supported and encapsulated, while the filler neck of the bladder is fully secured to the upper bodywork. In aircraft, this type of fuel vessel was considered a significant advance over conventional, hard metal and fiberglass tanks, which benefits, we can reasonably presume, would naturally ensue in a race car as well.

Would a riveted aluminum or molded fiberglass tank survive intact in the direct, high-speed side impact this vehicle suffered? No. They would not.

This would be a very silly thread if it weren't in such poor taste. I can't believe folks are still beating this dead horse. This very same photograph ran in this very thread four years and 1000 posts ago. (Post #582, Oct 29, 2007.) What are we trying to accomplish here? No offense, but it's not like any particular historical or technical expertise are being brought to bear to this topic. People are asking the same questions that were definitively answered years ago. They just don't like the answers, resulting in this endless and pointless rehash of an extremely sad and unfortunate event. It's creepy.

Good, I am glad some people have learnt a little bit about fires using gas or petrol. This whole "under the right conditions" nonsense needs to stop now. Some of the posts here are of a conspiracy theory mentality and do them no credit at all. Please stop now. The car was handling badly even at slower speeds. The poor guy lost it as many drivers would have and carrying a heavy fuel load it blew up on impact. How can any of you not see this simple truth?

Because to most of us, this "simple truth" is just BS. If the car was handling all that badly, how come it was one of the ten fastest on the track? Sure, if you go by the theory that 90 % of all racing cars back then were evil-handling brutes, then your statements are (barely) valid, but then again it's just stating the bleeding obvious. Otherwise, you're just endlessly repeating the same nonsense that's been debunked ages ago. I have to agree with the last poster, this thread has become very silly, pointless and of poor taste. I think it's time to close it.

If the thread has turned silly and should be closed, would you three like for me to post information I have received?

Henry

Sample:

It is almost impossible for someone with limited time, such as myself, to review the entire thread each time something is received (and I receive a lot..........some duplicated............and not posted).

I favor an approach of asking an apology for duplication rather than not having something documented to bring more light and accuracy to an accident that for so many decades produced downright inaccuracies and in some cases possible intentional misleading statements.

I have always been led to believe that MacDonald was a late addition to the Mickey Thompson team at Indy 1964.

Primarily because no one wanted to drive the Thompson cars in 1964.

This counters that belief.

From November 1963 time frame.......................six months prior to the 1964 race.

This may also explain why Dave is pictured above in the #82 car before new body was applied.

Trying to identify if that photo was taken at Indy....................................perhaps the sponsors listed on concrete wall can give us an idea of where and when. The infrastructure in photo looks a little different than Indy but I could be wrong.

This may have already appeared in the thread as a newspaper/magazine photograph. Not sure.

This looks like the original photograph as it is clear and crisp.

Interesting that the rear tires have both "Allstate" name and the famous "M/T" logo. And, it appears these tires were made by Firestone and not Armstrong. It also appears that a tire war was underway and the soft compound of the original tire was changed to a harder compound after some protest creating issues for the lighter Thompson cars.

So, perhaps Thompson and the team were indeed ahead of the curve in a lot of arrears. Click on "Shaking up Indy".

I have always been led to believe that MacDonald was a late addition to the Mickey Thompson team at Indy 1964.

Primarily because no one wanted to drive the Thompson cars in 1964.

This counters that belief.

From November 1963 time frame.......................six months prior to the 1964 race.

This may also explain why Dave is pictured above in the #82 car before new body was applied.

Trying to identify if that photo was taken at Indy....................................perhaps the sponsors listed on concrete wall can give us an idea of where and when. The infrastructure in photo looks a little different than Indy but I could be wrong.

Cropped version of that Indy diary - indicates MacDonald did test the car back in Nov ’63 ... with new 15” tires.

When (and possibly where) could this have taken place as we know the #82 car was raced with new bodywork in 1964.

Yes the photo is Indy, as are these from the motor trend article posted earlier. Closeup shows MacDonald & Carter testing the Thompson '63 body style .. but with the larger 15" tires required for '64. So this is likely the teams Nov '63 appearance and when Thompson realized that he would essentially need to completely redesign the car in order to improve stability.

This may have already appeared in the thread as a newspaper/magazine photograph. Not sure.

This looks like the original photograph as it is clear and crisp.

Interesting that the rear tires have both "Allstate" name and the famous "M/T" logo. And, it appears these tires were made by Firestone and not Armstrong. It also appears that a tire war was underway and the soft compound of the original tire was changed to a harder compound after some protest creating issues for the lighter Thompson cars.

In 1963, the Thompson cars used Firestone tires. In 1964, the tires were manufactured by Armstrong and bore the Allstate brand.

The '63 and '64 tires/cars are dead easy to tell apart: the '63 tires are 12 inches in wheel diameter, while the '64s are 15 inchers. You would think that after four years and 1600 posts folks would have such a simple and obvious thing fully sorted by now, yet here we are.

This is how the thread has gone on so interminably without accomplishing a thing. The same material is covered over and over and over and over and over -- and people still can't get the most basic facts straight.

Earlier in this post we had photos with the location of key cars listed and from them it appeared Jack Brabham could not have seen Dave spin coming off of turn 4 since Jack himself was barely into turn 3.

The one thing you have confirmed is when Masten told Jack about the cars and their handling problems. Perhaps Ovi can repost those pics

I wondered, this book by brabham, did he really write it himself or was it "ghostwritten" by the author and then read over and approved by Brabham instead of him gong back to that day, have him tell it and them bing written down? And the Ghostwriter thus being rseponsible for adding to the confusion about what Brabham said aboutrace day experiences and his location at the moment of the actual accident?